1. Technical Field
The present invention relates to a compression latch for a closure.
2. Description of the Prior Art
It is known to use compression latches in a variety of applications, for example when force is required to hold a closure in place, or when sealing of a closure (e.g. a door, window or access panel of a vehicle or an item of construction plant) is needed. Compression latches often incorporate a pivoting latch arm held against a closure surround by latch mechanism, and biased into an open position by a spring or other resiliently biased device. The latch mechanism holds the latch arm in a closed position so that pressure is applied by the latch to a closure to keep it shut and/or seal it. Upon release of the latch mechanism, the resilient biasing device causes the latch arm to pivot open enabling the associated closure to be opened. Compression latches are typically mounted in an aperture cut from the sheet metal material of the closure.
There can be difficulties with existing compression latches of this type. The latch arm must clear the closure surround when the latch is in a fully open position, so that it does not prevent the closure from being fully opened. Considerable force may be required to close a latch, particularly where the latch is required to seal a closure. It is known to increase the length of the lever handle to allow a greater amount of mechanical advantage to be applied to the latch arm whilst limiting the force required at the handle, but this leads to increased space requirement, and for a requirement for a larger aperture to be cut in the closure. In addition, the level of mechanical advantage is fixed throughout the range of motion of the lever.
Where the closure is relatively large, it may be desirable for additional “satellite” compression latches to be connected to the main latch, and operated from it, in order to provide optimal retention. One way in which this may be achieved is to utilise the pivot point of the main latch as a “power take-off” for shafts to connect the satellite latches. However, the location of this pivot point on known latches is too close to the face of the closure for the shafts to be able to rotate freely.
A known latch of this type is disclosed in GB2264530 (Southco). It is not possible to alter the relative motion of the handle and the latch arm of the latch disclosed in GB2264530. The only way to vary the mechanical advantage of that latch is to vary the length of the handle and the latch arm. In addition, the pivot point is too close to the closure face to act as a power take-off.
The present invention seeks to overcome, or at least mitigate, the problems of the prior art.